Matrix liquid crystal display

ABSTRACT

The invention relates to a matrix liquid crystal display containing integrated non-linear elements and a liquid crystal mixture which has a particularly high resistivity.

This is a division of application Ser. No. 07/458,695 filed Jan. 5,1990, U.S. Pat. No. 5,122,295.

The invention relates to a matrix liquid crystal display containing

two plane parallel support plates which together with a frame form acell,

integrated non-linear elements for switching individual picture elementson the support plates and

a nematic liquid crystal mixture which is present in the cell and has apositive dielectric anisotropy and high resistivity,

the liquid crystal mixture being based on the following components:

a) at least 10% by weight of a liquid-crystalline component B comprisingone or more compounds having a dielectric anisotropy of more than +1.5,

b) up to 90% by weight of a liquid-crystalline component A comprisingone or more compounds having a dielectric anisotropy of -1.5 to +1.5 ofthe general formula I ##STR1## in which R¹ and R² are each,independently of one another, n-alkyl, ω-fluoroalkyl or n-alkenyl havingup to 9 carbon atoms,

the rings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene,

Z¹ and Z² are each, independently of one another, --CH₂ CH₂ -- or asingle bond,

and

m is 0, 1 or 2, and

c) 0 to 20% by weight of a liquid-crystalline component C comprising oneor more compounds having a dielectric anisotropy of less than -1.5, andthe nematic liquid crystal mixture having a nematic phase range of atleast 60° C., a maximum viscosity at 20° C. of 30 mPa.s and a meandielectricity constant ε≦8.

Matrix liquid crystal displays (MLC displays) according to the preambleare known. For example, active elements (i.e. transistors) can be usedas non-linear elements for the individual switching of the individualpicture elements. This is referred to as an "active matrix", in whichtwo types can be distinguished:

1. MOS (metal oxide semiconductor) transistors on a silicon wafer as thesubstrate.

2. Thin film transistors (TFT) on a glass plate as the substrate.

In the case of type 1, dynamic scattering or the guest/host effect isusually used as the electrooptical effect. The use of single-crystalsilicon as the substrate material limits the size of the display, since,even if different partial displays are put together in the form ofmodules, difficulties arise at the joints.

In the case of the more promising type 2, which is preferred, the TNeffect is usually used as the electrooptical effect. Two technologiesare distinguished: TFTs consisting of compound semiconductors, such as,for example, CdSe, or TFTs based on polycrystalline or amorphoussilicon. The latter technology is the subject of intense developmentwork worldwide.

The TFT matrix is disposed on the inside surface of one of the glassplates of the display, while the other glass plate carries thetransparent counter electrode on its inside surface. Compared with thesize of the picture element electrode, the TFT is very small andessentially does not interfere with the picture. This technology canalso be extended to picture displays in fully satisfactory colours byarranging a mosaic of red, green and blue filters in such a manner thateach filter element is opposite to a switchable picture element.

The TFT displays usually operate as TN cells which contain crossedpolarizers in transmission and are illuminated from behind.

The term MLC displays in this context comprises each matrix displaywhich has integrated non-linear elements, i.e. apart from the activematrix also displays which contain passive elements such as varistors ordiodes (MIM=metal/insulator/metal).

MLC displays of this type are in particular suitable for TV applications(e.g. portable TVs) or for highly informative displays in automobile andaircraft construction. In addition to problems regarding the angledependency of the contrast and the switching times, difficulties in MLCdisplays arise from the insufficient resistivity of the liquid crystalmixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E.,SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage DiodeRings, p. 141 ff, Paris; STROMER, M., Proc. Eurodisplay 84, Sept. 1984:Design of Thin Film Transistors for Matrix Addressing of TelevisionLiquid Crystal Displays, p. 145 ff, Paris]. With decreasing resistivity,the contrast of an MLC display deteriorates. Since the resistivity ofthe liquid crystal mixture usually decreases by interaction with theinside surfaces of the displays over the lifetime of an MLC display, ahigh (initial) resistance is very important for achieving acceptableservice lives.

Therefore, there is still a high demand for MLC displays which have veryhigh resistivity in combination with a large range of operatingtemperatures, short switching times and low threshold voltage.

The object of the invention is to provide MLC displays which do not oronly to a small extent have the above disadvantages and, at the sametime, have very high resistivities.

It has now been found that this object can be achieved by using nematicliquid crystal mixtures in these display elements, which mixtures arebased on the abovementioned components A, B and C, B and C, or B.

Accordingly, the invention relates to an MLC display containing

two plane parallel support plates which together with a frame form acell,

integrated non-linear elements for switching individual picture elementson the support plates and

a nematic liquid crystal mixture which is present in the cell and has apositive dielectric anisotropy and high resistivity,

the liquid crystal mixture being based on the following components:

a) at least 10% by weight of a liquid-crystalline component B comprisingone or more compounds having a dielectric anisotropy of more than +1.5,

b) up to 90% by weight of a liquid-crystalline component A comprisingone or more compounds having a dielectric anisotropy of -1.5 to +1.5 ofthe general formula I ##STR2## in which R¹ and R² are each,independently of one another, n-alkyl, ω-fluoroalkyl or n-alkenyl havingup to 9 carbon atoms,

the rings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene,

Z¹ and Z² are each, independently of one another, --CH₂ CH₂ -- or asingle bond,

and

m is 0, 1 or 2, and

c) 0 to 20% by weight of a liquid-crystalline component C comprising oneor more compounds having a dielectric anisotropy of less than -1.5, andthe nematic liquid crystal mixture having a nematic phase range of atleast 60° C., a maximum viscosity at 20° C. of 30 mPa.s and a meandielectricity constant ε≦8.

The invention also relates to the corresponding liquid crystal mixtures,in particular for use in MLC displays. However, the mixtures are alsosuitable for many other applications, such as, for example, TN, STN orOMI.

Nematic liquid crystal mixtures which instead of the compounds of theformula I contain analogous compounds in which one of the radicals R¹and R² is n-alkyl and the other is n-alkoxy are known and commerciallyutilized in various designs. However, these liquid crystal mixtures aredistinguished by values for the resistivity which are too low and areoften between 5×10⁹ and 1.1×10¹¹ Ωcm or less at 20°. The correspondingMLC displays have values for the resistivity which are too low for somecommercial applications.

The resistivity of liquid crystal mixtures is in general high, if thedielectric anisotropy is small, since the polar components which arepresent in mixtures which have a high Δε have a stabilizing effect onions and thus lead to high conductivity or low resistance. Surprisingly,it has now been found that the resistivity is particularly high, if themean dielectricity constant ε [=1/3(2ε.sub.⊥ +ε₁₁)] is small and, at thesame time, the dielectrically neutral (Δε from -1.5 to +1.5) componentsof the liquid crystal mixture do not contain any functional groups suchas, for example, aromatically bound alkoxy or ester functions. Thedielectrically positive (Δε≧1.5) components usually carry terminal cyanogroups. However, in the mixtures according to the invention, it ispreferred to use, in addition to compounds which have a terminal cyano,also those which have a terminal --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃,--OCHF₂, --OCF₂ CF₂ H or --OC₂ F.sub. 5.

However, component B can also substantially consist only ofnitrile-containing compounds, of which those compounds of the formulaeIIa to IIf where X is CN are preferred. In this case, the liquid crystalmixture essentially consists of components A, B and C, or A and B.

Particular preference is given to liquid crystal mixtures which containnitrile-containing and nitrile-free, fluorinated compounds, the latterpreferably conforming to the formulae IIa to IIf in which X is F, Cl,--CF₃, --CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅.

The ratio of nitrile-free to nitrile-containing compounds in component Bis preferably >1:1, in particular >2:1. Particularly preferred rangesare 2.5:1 to 6:1.

However, very particular preference is given to liquid crystal mixtureswhose component B essentially consists of nitrile-free, fluorinatedcompounds. Preferably, the abovementioned preferred compounds of theformulae IIa to IIf are used.

`Essentially` is understood to mean that the amount of further compoundsin the corresponding component is ≦20%, in particular ≦10%.

Preference is also given to liquid crystal mixtures whose component Bcontains compounds whose end groups are chlorinated. Compounds of thistype are known to one skilled in the art and preferably conform to theformulae IIa to IIf where X is Cl. In a particularly preferredembodiment, the mixtures contain one or more compounds of the formulaIIa to IIf in which A² --X or A³ --X is ##STR3## where X is CF₃, --OCF₃,--OCHF₂ or Cl. Furthermore, component B can also contain tetranuclearcompounds, for example in accordance with formulae IIc to IIf in whichone of the rings A¹ to A³ is present twice.

In a particularly preferred embodiment, the mixtures contain compoundswhich have a terminal nitrile and are present in component B in anamount from 0 to 50% by weight. Particular preference is given tomixtures which do not contain any compounds which have a terminalnitrile. Surprisingly, it has been found that groups such as --OCF₃,--OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅ have a considerably less stabilizingeffect in the displays than --OCH₃ or --OC₂ H₅. The same is true foraliphatically bound alkoxy (compounds of the formulae III and IV).

The mixtures according to the invention preferably have a resistivity of≦10¹² Ω×cm, particularly preferably >10¹³ Ω×cm, at 20°. The mean ε ispreferably ≦7, in particular ≦5.

The values of dielectric anisotropy of the individual compounds ofcomponents A to C are determined at 20° by extrapolation from a polarmixture (containing 24% of p-trans-4-propylcyclohexylbenzonitrile, 36%of p-trans-4-pentylcyclohexylbenzonitrile, 25% ofp-trans-4-heptylcyclohexylbenzonitrile and 15% of4-cyano-4'-(trans-4-pentylcyclohexyl)biphenyl), if the compound to bedetermined contains a dipole along the longitudinal axis of themolecule, or from a neutral mixture (containing 22% oftrans-1-p-ethylphenyl-4-propylcyclohexane, 20% oftrans-1-p-methoxyphenyl-1-propylcyclohexane, 15% oftrans-1-p-ethoxyphenyl-4-propylcyclohexane, 19% of4-ethyl-4-(trans-4-propylcyclohexyl)biphenyl, 14% of4-ethyl-4'-(trans-4-pentylcyclohexyl)biphenyl, 5% of4,4'-bis(trans-4-propylcyclohexyl)biphenyl and 5% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)biphenyl) inthe case of neutral compounds.

The liquid crystal mixtures according to the invention make it possibleto achieve a high value for the resistivity in combination with lowviscosities, which allows to produce excellent MLC displays. The MLCdisplays according to the invention preferably operate in the firsttransmission minimum according to Gooch and Tarry [C. H. Gooch and H. A.Tarry, Electron. Lett. 10, 2-4, 1974; C. H. Gooch and H. A. Tarry, Appl.Phys., Vol. 8, 1575-1584, 1975], in which case in addition toparticularly favourable electrooptical properties such as, for example,high steepness of the characteristic curve and low angle dependence ofthe contrast (German Patent Specification 3,022,818) in combination withthe same threshold voltage as in an analogous display, a smallerdielectric anisotropy is sufficient in the second minimum. This makes itpossible to achieve significantly higher resistivities in the firstminimum, when the mixtures according to the invention are used.

The viscosity at 20° C. is preferably ≦25 mPa.s. The nematic phase rangeis preferably at least 70°, in particular at least 80°. Preferably, thisrange extends at least from -20° to +70°.

The individual compounds of the formulae I to IV and their subformulaewhich can be used in the MLC displays according to the invention areeither known or can be prepared analogously to known compounds.

Preferred liquid crystal mixtures to be used according to the inventioncontain a total of, preferably, 10% to 90%, in particular 20% to 90%, ofcompounds of the formula I. If component B is not composed predominantlyof strongly dielectrically positive nitrile components but predominantlyonly of weakly dielectrically positive compounds such as, for example,the fluorinated compounds mentioned below, component A can under certaincircumstances be omitted entirely, and the mixtures according to theinvention can in this special embodiment be solely based on component Band, if desired, component C. Particular preference is given to liquidcrystal mixtures whose component B contains one or more compoundsselected from the group consisting of compounds of the formulae IIa toIIf ##STR4## in which R is n-alkyl or n-alkenyl of up to 9 carbon atoms,

X is cyano, --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂ , --OCF₂ CF₂ Hor --OC₂ F₅, and

the rings A¹, A.sup. 2 and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene.

Preferably, component B contains compounds of the formulae IIa to IIf inwhich X is cyano and compounds of the formulae IIa to IIf in which X is--NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅,and the amount of cyano compounds in component B is 0 to 50% by weight.

In a particularly preferred embodiment, component B does not contain anycompounds of the formulae IIa to IIf in which X is cyano.

In the compounds of the partial formulae IIa to IIf, X is preferably F,Cl, CF₃, --OCF₃, --OCHF₂ or --CHF₂.

The rings A¹, A² and A³ are each preferably, independently of oneanother, trans-1,4-cyclohexylene or 1,4-phenylene. In a preferredembodiment, one of the rings A¹, A² and A³ is 2- or3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene. The ring bound toX (i.e. A² in IIa and IIb and A³ in IIc to IIf) is preferably1,4-phenylene which is unsubstituted or even mono- or di-substituted byfluorine. A₂ --X and A³ --X are preferably a group selected from theformulae (a) to (h): ##STR5## of which (a) , (b), (d), (f), (g) and (h)are particularly preferred.

Particularly preferred smaller groups of compounds are listed below:##STR6##

In the partial formulae IIa1 to IIf3, R is in each case n-alkyl orn-alkenyl of up to 9 carbon atoms. Y and Z are each, independently ofone another, H or F although one or two of the radicals Y and Z ispreferably fluorine. However, X is preferably F, Cl, --CF₃ --, --OCF₃ or--OCHF₂.

Component B preferably represents 10% to 100%, in particular 20% to 80%,of the mixtures according to the invention.

Component A preferably contains one or more compounds selected from thegroup consisting of II1 to II7: ##STR7## in which R¹ and R² have themeaning given in claim 1.

Preferably, component A additionally contains one or more compoundsselected from the group consisting of II8 to II20: ##STR8## in which R¹and R² have the meaning given in claim 1 and the 1,4-phenylene groups inII8 to II17 can each, independently of one another, also be mono- orpolysubstituted by fluorine.

Furthermore, component A preferably additionally contains one or morecompounds selected from the group consisting of II21 to II25: ##STR9##in which R¹ and R² have the meaning given in claim 1 and the1,4-phenylene groups in II21 to II25 can each, independently of oneanother, also be mono- or polysubstituted by fluorine.

Finally, those mixtures are preferred whose component A contains one ormore compounds selected from the group consisting of II26 and II27:##STR10## in which C_(r) H_(2r+1) is a straight-chain alkyl group of upto 7 carbon atoms.

In some cases, the addition of compounds of the formula ##STR11## inwhich R¹ and R² have the meaning given in claim 1

and

Z⁰ is a single bond, --CH₂ CH₂ --, ##STR12## or proves to beadvantageous for suppressing smectic phases, although the resistivity isthereby lowered. Whether and in which amount these compounds should beadded for achieving optimum parameter combinations for practicalapplication can easily be determined by one skilled in the art. Usually,less than 15%, in particular 5-10%, are used.

Further preference is given to liquid crystal mixtures which, inaddition to components A, B and C, additionally contain one or morecompounds selected from the group consisting of III and IV: ##STR13## inwhich R¹ and R² have the abovementioned meaning and/or one or morecompounds selected from the group consisting of V and VI ##STR14## inwhich R¹ and R² have the abovementioned meaning and/or one or morecompounds selected from the group consisting of VII to XI ##STR15## inwhich R¹ and R² have the abovementioned meaning and s is 0 or 1.

The amounts of the compounds of the formulae III to XI in the mixturesaccording to the invention (preferred ranges) can be seen from the tablebelow:

Sum of compounds III and IV: 0% to 40%, preferably 10% to 30%

Sum of compounds V and VI: 0% to 40%, preferably 5% to 20%

Sum of compounds VII to XI: 0% to 20%, preferably 5% to 15%

It goes without saying that the mixtures according to the invention,which preferably consist essentially of the compounds mentioned aspreferred for components A to C, may additionally also contain furthercompounds not mentioned here explicitly. However, this leads in manycases to more unfavourable properties. One skilled in the art can easilydetermine whether and in which amounts further compounds can be used.

The design of the MLC display according to the invention which consistsof polarizers, electrode base plates and electrodes which have beensubjected to surface treatment is that which is customary for this typeof display. The definition of customary design is in this case verybroad and also comprises all modifications and alterations of the MLCdisplay, in particular also matrix display elements based on poly-Si TFTor MIM.

However, a significant difference between the displays according to theinvention and those which have been customary so far and are based onthe twisted nematic cell is the selection of the liquid crystalparameters of the liquid crystal layer.

The preparation of the liquid crystal mixtures to be used according tothe invention is carried out in the usual manner. As a rule, the desiredamount of the components used in a minor amount is dissolved in thecomponents which constitute the major component, advantageously atelevated temperature. It is also possible to mix solutions of thecomponents in an organic solvent, for example in acetone, chloroform ormethanol, and remove the solvent again after the mixing, for example bydistillation.

The dielectrics can also contain further additives known to one skilledin the art and described in the literature. For example, 0-15%pleochroic colorants or chiral doping substances can be added.

The examples which follow are intended to illustrate the inventionwithout limiting it. Hereinbefore and hereinafter all temperatures aregiven in °C. The percentages are by weight.

EXAMPLE 1

A matrix liquid crystal display of the TFT type containing a nematicliquid crystal mixture consisting of

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of p-trans-4-butylcyclohexylbenzonitrile,

22% of trans-1-p-propylphenyl-4-pentylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

9% of E-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a resistivity of 3×10¹² Ωcm. The nematic mixture has a clear pointof 91°, a viscosity of 18 mPa.s at 20°, a mean DC of 5.0 and an opticalanisotropy of 0.118.

EXAMPLE 2

A nematic mixture consisting of

7% of p-trans-4-propylcyclohexylbenzonitrile,

13% of p-trans-4-butylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

7% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

7% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 93°, a viscosity of 19 mPa.s, a mean DC of 5.4, aΔn of 0,107 and a resistivity of 2.5×10¹² Ωcm.

EXAMPLE 3

A nematic mixture consisting of

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

17% of trans-1-p-propylphenyl-4-pentylcyclohexane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

3% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 88°, a viscosity of 15.2 mPa.s, a mean DC of 4.3, aΔn of 0.078 and a resistivity of 8.6×10¹³ Ωcm. This mixture isparticularly suitable for operation in the first minimum according toGooch and Tarry at a threshold voltage of 2.7 V.

EXAMPLE 4

A nematic mixture consisting of

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

12% of trans-1-p-propylphenyl-4-pentylcyclohexane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl-ethane,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

4% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 91°, a Δn of 0.076, a mean DC of 4.2 and aresistivity of 7.3×10¹³ Ωcm.

EXAMPLE 5

A nematic mixture consisting of

13% of p-trans-4-propylcyclohexylbenzonitrile,

8% of p-trans-4-butylcyclohexylbenzonitrile,

15% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

17% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 96°, a Δn of 0.103, a mean DC of 4.9 and aresistivity of 1.0×10¹³ Ωcm. This mixture is particularly suitable foroperation in the first minimum according to Gooch and Tarry at athreshold voltage of 2.3 V.

EXAMPLE 6

A nematic mixture consisting of

13% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

15% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

12% of trans,trans-4-pentyl-4'-(2-fluoroethyl)-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 99°, a Δn of 0,097, a mean DC of 4.1 and aresistivity of 7.8×10¹³ Ωcm. This mixture is particularly suitable foroperation in the first minimum according to Gooch and Tarry at athreshold voltage of 2.9 V.

EXAMPLE 7

A nematic mixture consisting of

16% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

11% of trans,trans-4-pentyl-4'-(2-fluoroethyl)-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 99.5°, a Δn of 0.100, a mean DC of 4.2 and aresistivity of 7.5×10¹³ Ωcm. This mixture is particularly suitable foroperation in the first minimum according to Gooch and Tarry at athreshold voltage of 2.7 V.

EXAMPLE 8

A nematic mixture consisting of

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

9% of trans-1-p-propylphenyl -4-pentylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

9% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of-4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 93.4°, a Δn of 0.108, a mean DC of 4.4 and aresistivity of 1.3×10¹³ Ωcm. The viscosity at 20° is 18.4 mPa.s.

EXAMPLE 9

A nematic mixture consisting of

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

11% of trans-1-p-propylphenyl-4-pentylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

8% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 89.8°, a Δn of 0.102, a mean DC of 4.4, aresistivity of 1.5×10¹³ Ωcm and a viscosity of 18.1 mPa.s.

EXAMPLE 10

A nematic mixture consisting of

8% of p-trans-4-propylcyclohexyl-fluorobenzene,

7% of p-trans-4-pentylcyclohexyl-fluorobenzene,

8% of p-trans-4-hexylcyclohexyl-fluorobenzene,

7% of p-trans-4-heptylcyclohexyl-fluorobenzene,

5% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(2,3',4'-trifluorobiphenyl-4-yl)-ethane,

5% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(2,3',4'-trifluorobiphenyl-4-yl)-ethane,

8% of trans,trans-1-(p-ethylphenyl)-4-propyl-cyclohexylcyclohexane,

7% of trans,trans-1-(p-propylphenyl)-4-pentyl-cyclohexylcyclohexane,

8% of trans,trans-1-(p-fluorophenyl)-4-propyl-cyclohexylcyclohexane,

7% of trans,trans-1-(p-fluorophenyl)-4-pentyl-cyclohexylcyclohexane,

6% oftrans,trans-1-(p-trifluoromethoxyphenyl)-4-propyl-cyclohexylcyclohexane,

4% oftrans,trans-1-(p-trifluoromethoxyphenyl)-4-pentyl-cyclohexylcyclohexane,

6% of trans,trans-1-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-4-propyl-cyclohexylcyclohexane,

4% of trans,trans-1-[p-(1,1,2,2-tetrafluoroethoxy)phenyl]-4-pentyl-cyclohexylcyclohexane,

3% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

3% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and

4% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 92°, a Δn of 0.099, a mean DC of 4.1, a resistivityof 5.4×10¹³ Ωcm and a viscosity of only 14 mPa.s.

EXAMPLE 11

A nematic mixture consisting of

10% of p-trans-4-propylcyclohexylbenzonitrile,

22% of trans-1-p-propylphenyl-4-pentylcyclohexane,

5% of 4,4'-bis-propylbiphenyl,

5% of trans,trans-4-propyl-4'-methyl-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

5% of 1,4-bis-(trans-4-propylcyclohexyl)-benzene,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

9% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

5% of1-(trans-4-propylcyclohexyl)-2-(4'-ethyl-2'-fluorobiphenyl-4-yl)-ethane,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 95°, a viscosity of 16 mPa.s, a Δn of 0.113, a meanDC of 3.8 and a resistivity of 7×10¹³ Ωcm.

EXAMPLE 12

A nematic mixture consisting of

17% of p-trans-4-propylcyclohexylbenzonitrile,

11% of trans-1-p-propylphenyl-4-pentylcyclohexane,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

8% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of E [sic]-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 90°, a viscosity of 18 mPa.s and a Δn of 0.102.

EXAMPLE 13

A nematic mixture consisting of

14% of p-trans-4-propylcyclohexylbenzonitrile,

14% of trans-1-p-fluorophenyl-4-pentylcyclohexane,

14% of trans-1-p-fluorophenyl-4-heptylcyclohexane,

10% of trans-1-p-propylphenyl-4-pentylcyclohexane,

6% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

6% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

5% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

5% of 4,4'-bis-(trans-4-propylcyclohexyl)-biphenyl,

5% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

5% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl,

5% of 4,4'-bis-(trans-4-pentylcyclohexyl)-biphenyl,

5% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-biphenyl and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 95°, a viscosity of 17 mPa.s and a Δn of 0.105.

The following mixtures are very suitable for MLC displays:

EXAMPLE 14

A nematic mixture is prepared which consists of:

10% of 1-(trans-4-pentylcyclohexyl)-2-(4'-fluorobiphenyl-4-yl)-ethane,

17% of trans-1-p-propylphenyl -4-pentylcyclohexane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-(trans-4-pentylcyclohexyl)-2-[trans-4-(3,4-difluorophenyl)-cyclohexyl]-ethane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

3% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 15

A nematic mixture is prepared which consists of:

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

12% of trans,trans-4-propyl-4'-methoxymethyl-cyclohexylcyclohexane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

4% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 16

A nematic mixture is prepared which consists of:

13% of 1-(trans-4-propylcyclohexyl)-2-(p-cyanophenyl)-ethane,

8% of p-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-benzonitrile,

18% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

17% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

4% of 1-(trans-4-propylcyclohexyl)-2-(trans-4-pentylcyclohexyl)-ethane,

4% of1-[P-(trans-4-propylcyclohexyl-phenyl]-2-(trans-4-pentylcyclohexyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 17

A nematic mixture is prepared which consists of:

13% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

15% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

12% of 1-(trans-4-pentylcyclohexyl)-4-propylcyclohex-1-ene,

4% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-4-propylcyclohex-1-ene,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 18

A nematic mixture is prepared which consists of:

16% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

11% of trans,trans-4-pentyl-4'-(2-fluoroethyl)-cyclohexylcyclohexane,

4% of 1-(trans-4-propylcyclohexyl)-2-(4-pentylbiphenyl-4'-yl)-ethane,

4% of 1-[p-(trans-4-pentylcyclohexyl)-phenyl]-2-(p-propylphenyl)-ethane,

4% of1-(trans-4-pentylcyclohexyl)-2-[trans-4-(p-propylphenyl)-cyclohexyl]-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 19

A nematic mixture is prepared which consists of:

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-ethoxy-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

9% of trans-1-p-propylphenyl -4-pentylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

9% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 20

A nematic mixture is prepared which consists of:

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of trans,trans-4-pentyl-4'-methoxy-cyclohexylcyclohexane,

13% of trans,trans-4-propyl-4'-propoxy-cyclohexylcyclohexane,

11% of trans-1-p-propylphenyl-4-pentylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

8% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

8% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 21

A nematic liquid crystal mixture is prepared which consists of:

17% of p-trans-4-propylcyclohexylbenzonitrile,

13% of p-trans-4-butylcyclohexylbenzonitrile,

22% of trans-1-p-propylphenyl-4-pentylcyclohexane,

4% of1-(trans-4-propylcyclohexyl)-2-(4-ethyl-2,3-difluorobiphenyl-4'-yl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

9% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

9% of 4-ethyl -4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 22

A nematic mixture is prepared which consists of:

15% of p-trans-4-propylcyclohexylbenzonitrile,

11% of p-trans-4-butylcyclohexylbenzonitrile,

11% of trans,trans-4-pentyl-4'-fluoromethyl-cyclohexylcyclohexane,

11% of trans,trans-4-propyl-4'-fluoromethyl-cyclohexylcyclohexane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

4% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,

4% of 2-p-fluorophenyl-5-hexylpyrimidine,

4% of 2-p-fluorophenyl-5-pentylpyridine,

7% of 4-ethyl-4'-(trans-4-propylcyclohexyl)-biphenyl,

7% of 4-ethyl-4'-(trans-4-pentylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and

6% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 23

A nematic mixture consisting of:

14% of p-trans-4-propylcyclohexylbenzonitrile,

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

10% of p-trans-4-heptylcyclohexyl-fluorobenzene,

20% of p-trans-4-pentylcyclohexyl-difluoromethoxybenzene,

6% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

6% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

5% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,

5% of 4,4'-bis-(trans-4-propylcyclohexyl)-biphenyl,

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-biphenyl,

5% of 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl,

5% of 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,

5% 5% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-biphenyl, and

5% of4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

has a clear point of 93°, a viscosity of 17 mPa.s, a Δn of 0.105 and ahigh resistivity.

EXAMPLE 24

A nematic mixture consisting of

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

10% of p-trans-4-hexylcyclohexyl-fluorobenzene,

10% of p-trans-4-heptylcyclohexyl-fluorobenzene,

20% ofp-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

10% of 4-trifluoromethoxy-4'-(trans-4-pentylcyclohexyl)-biphenyl

has a clear point of 80°, a Δn of 0.079, a threshold voltageV.sub.(10/0/20) of 2.27 volt and a very low viscosity.

EXAMPLE 25

A nematic mixture consisting of

25% of p-trans-4-propylcyclohexyl-trifluoromethoxybenzene,

20% of 4-trifluoromethoxy-4'-(trans-4-pentylcyclohexyl)-biphenyl,

15% ofp-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

20% of1-[trans-4-(trans-4-pentylcyclohexyl-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane

has a clear point of 54°, a Δn of 0.088, a threshold voltageV.sub.(10/0/20) of 2.18 volt and a very low viscosity.

EXAMPLE 26

A nematic mixture consisting of

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

10% of p-trans-4-hexylcyclohexyl-fluorobenzene,

12% of p-trans-4-hexylcyclohexyl-difluoromethoxybenzene,

10% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

11% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,

11% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

11% of 1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

11% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of p-[trans-4-(trans-4-propylcyclohexyl]-trifluoromethoxybenzene and

4% of 4,4'-bis-(trans-4-pentylcyclohexyl)-biphenyl

has a clear point of 87°, a Δn of 0.0798; a dielectric anisotropy of+6.5, a threshold voltage of V.sub.(10/0/20) of 2.25 volt and a very lowviscosity.

EXAMPLE 27

A nematic mixture consisting of

10% of p-trans-4-propylcyclohexyl-trifluoromethoxybenzene,

10% of p-trans-4-propylcyclohexyl-difluoromethoxybenzene,

10% of1-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcylcohexyl)[sic]-cyclohexyl]-2-(p-fluorophenyl)-ethane,

10% of1-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-2-(p-fluorophenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcylcohexyl)[sic]-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

15% of1-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

10% of1-[trans-4-(trans-4-propylcylcohexyl)[sic]-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,

10% ofp-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-trifluoromethoxybenzeneand

5% of 4-trifluoromethoxy-4'-(trans-4-pentylcyclohexyl)-biphenyl

has a clear point of 81°, a Δn of 0.0795, a threshold voltageV.sub.(10/0/20) of 2.47 volt and a very low viscosity.

EXAMPLE 28

A nematic mixture consisting of

10% of p-trans-4-propylcyclohexyl-trifluoromethoxybenzene,

25% of p-trans-4-pentylcyclohexyl-difluoromethoxybenzene,

15% ofp-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,

15%of-1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

15% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,and

20% of 4-trifluoromethoxy-4'-trans-4-pentylcyclohexylbiphenyl

has a clear point of 71°, a Δn of 0.0878, a Δε of +6.1, a thresholdvoltage V.sub.(10/0/20) of 2.09 volt and a viscosity of 12 mPa.s at 20 °C.

EXAMPLE 29

A nematic mixture consisting of

10% of p-trans-4-pentylcyclohexyl-fluorobenzene,

15% of p-trans-4-hexylcyclohexyl-fluorobenzene,

15% of p-trans-4-heptylcylcohexyl[sic]-fluorobenzene,

20% ofp-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,

20% of1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,and

20% of1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,

has a clear point of 65°, a viscosity of 11 mPa.s at 20°, a Δn of 0.074,a Δε of +5.6 and a threshold voltage V.sub.(10/0/20) of 2.06 volt.

The composition of the mixtures of Examples 30 to 58 is given below, theindividual compounds being coded as follows:

PCH-301: trans-1-p-methoxyphenyl-4-propylcyclohexane

CCH-301: trans,trans-4-methoxy-4'-propylcyclohexylcyclohexane

CBC-33F: 4,4'-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl

CBE-55F: 4,4'-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl

CBC-53F:4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclcohexyl)[sic]-2-fluorobiphenyl

CBC-33: 4,4'-bis-(trans-4-propylcyclohexyl)-biphenyl

CBC-55: 4,4'-bis-(trans-4-pentylcyclohexyl)-biphenyl

CBC-53:4-(trans-4-pentylcyclohexyl)-4'-(trans-4-propylcyclohexyl)-biphenyl

ECCP-33:1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(p-propylphenyl)-ethane

CCH-51F: trans,trans-4-fluoromethyl-4'-pentylcyclohexylcyclohexane

CCH-31F: trans,trans-4-fluoromethyl-4'-propylcyclohexylcyclohexane

PTP -102: 4-methyl-4'-ethoxy-tolan

PTP -201: 4-methoxy-4'-ethyl-tolan

CPTP-301: 4-(trans-4-propylcyclohexyl)-4'-methoxy-tolan

CPTP-302: 4-(trans-4-propylcyclohexyl)-4'-ethoxy-tolan

CPTP-303: 4-(trans-4-propylcyclohexyl)-4'-propoxy-tolan

PCH-5F: trans-1-p-fluorophenyl-4-pentylcyclohexane

PCH-6F: trans-1-p-fluorophenyl-4-hexylcyclohexane

PCH-7F: trans-1-p-fluorophenyl-4-heptylcyclohexane

EPCH-20CF₂ :1-(trans-4-ethylcyclohexyl)-2-(p-trifluoromethoxyphenyl)-ethane

EPCH-30CF₂ :1-(trans-4-propylcyclohexyl)-2-(p-trifluoromethoxyphenyl)-ethane

EPCH-50CF₃ :1-(trans-4-pentylcyclohexyl)-2-(p-trifluoromethoxyphenyl)-ethane

EPCH-70CF₃ :1-(trans-4-heptylcyclohexyl)-2-(p-trifluoromethoxyphenyl)-ethane

PCH-30CF₃ : trans-1-p-trifluoromethoxyphenyl-4-propylcyclohexane

PCH-50CF₃ : trans-1-p-trifluoromethoxyphenyl-4-pentylcyclohexane

ECCP-30CF₃ :1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane

ECCP-50CF₃ :1-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane

CCP-20CF₃ :p-[trans-4-(trans-4-ethylcyclohexyl)cyclohexyl]-trifluoromethoxybenzene

CCP-30CF₃ :p-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-trifluoromethoxybenzene

CCP-40CF₃ :p-[trans-4-(trans-4-butylcyclohexyl)cyclohexyl]-trifluoromethoxybenzene

CCP-50CF₃ :p-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-trifluoromethoxybenzene

BCH-30CF₃ : 4-trifluoromethoxy-4'-(trans-4-propylcyclohexyl)-biphenyl

ECCP-3F.F:1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(3,4-difluorophenyl)-ethane

ECCP-5F.F:1-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-2-(3,4-difluorophenyl)-ethane

CCP-3F.F:4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-1,2-difluorobenzene

CCP-5F.F:4-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-1,2-difluorobenzene

CCP-3F: 4-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl)-fluorobenzene

ECCP-3F:1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(p-fluorophenyl)-ethane

ECCP-5F:1-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-2-(p-fluorophenyl)-ethane

CP-3F: p-fluorophenyltrans-4-(trans-4-propylcyclohexyl)-cyclohexanecarboxylate

CP-5F: p-fluorophenyltrans-4-(trans-4-propylcyclohexyl)-cyclohexanecarboxylate

PYP-5F: 2-p-fluorophenyl-5-pentylpyrimidine

PYP-6F: 2-p-fluorophenyl-5-hexylpyrimidine

PYP-7F: 2-p-fluorophenyl-5-heptylpyrimidine

PYP-30CF₃ : 2-p-trifluoromethoxyphenyl-5-propylpyrimidine

PYP-50CF₃ : 2-p-trifluoromethoxyphenyl-5-pentylpyrimidine

PYP-70CF₃ : 2-p-trifluoromethoxyphenyl-5-heptylpyrimidine

PCH-3: p-trans-4-propylcyclohexyl-benzonitrile

PCH-4: p-trans-4-butylcyclohexyl-benzonitrile

PCH-5: p-trans-4-pentylcyclohexyl-benzonitrile

ECCP-3:1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(p-cyanophenyl)-ethane

ECCP-3CF₃ :1-[trans-4-(trans-4-propylcyclohexyl)cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane

ECCP-5CF₃ :1-[trans-4-(trans-4-pentylcyclohexyl)cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane

PYP-5N.F: 2-(3-fluoro-4-cyanophenyl)-5-pentylpyrimidine

PYP-7N.F: 2-(3-fluoro-4-cyanophenyl)-5-heptylpyrimidine

PCH-30CF₂ : trans-1-p-difluoromethoxyphenyl-4-propylcyclohexane

PCH-50CF₂ : trans-1-p-difluoromethoxyphenyl-4-pentylcyclohexane

PCH-30CF₂ : trans-1-p-difluoromethoxyphenyl-4-propylcyclohexane

PCH-53: trans-1-p-propylphenyl-4-pentylcyclohexane

    ______________________________________                                        Example 30            Example 31                                              PCH-301    10.00      PCH-3OCF.sub.2                                                                           9.00                                         PCH-7F     4.00       PCH-4OCF.sub.2                                                                           8.00                                         EPCH-3OCF.sub.3                                                                          9.00       PCH-5OCF.sub.2                                                                           9.00                                         EPCH-7OCF.sub.3                                                                          5.00       CCH-301    7.00                                         CCP-3OCF.sub.3                                                                           13.00      CCP-3OCF.sub.3                                                                           13.00                                        CCP-5OCF.sub.3                                                                           12.00      CCP-5OCF.sub.3                                                                           12.00                                        ECCP-30CF.sub.3                                                                          12.00      ECCP-3OCF.sub.3                                                                          8.00                                         ECCP-5OCF.sub.3                                                                          8.00       ECCP-5OCF.sub.3                                                                          6.00                                         ECCP-3F.F  12.00      ECCP-3F.F  9.00                                         ECCP-3F    8.00       ECCP-3F    6.00                                         CBC-33F    2.00       CBC-33F    5.00                                         CBC-53F    3.00       CBC-53F    4.00                                         CBC-55F    2.00       CBC-55F    4.00                                         Example 32            Example 33                                              CCH-301    7.00       PCH-5F     13.0                                         PCH-5F     12.00      PCH-7F     10.0                                         PCH-7F     9.00       CCP-3OCF.sub.3                                                                           13.0                                         CCP-3OCF.sub.3                                                                           13.00      CCP-4OCF.sub.3                                                                           11.0                                         CCP-5OCF.sub.3                                                                           12.00      CCP-5OCF.sub.3                                                                           12.0                                         ECCP-3OCF.sub.3                                                                          11.00      ECCP-3OCF.sub.3                                                                          11.0                                         ECCP-5OCF.sub.3                                                                          8.00       ECCP-5OCF.sub.3                                                                          8.0                                          ECCP-3F.F  12.00      ECCP-3F.F  9.0                                          ECCP-3F    7.00       ECCP-5F.F  6.0                                          CBC-33F    3.00       CBC-33F    3.0                                          CBC-53F    3.00       CBC-53F    2.0                                          CBC-55F    3.00       CBC-55F    2.0                                          Example 34            Example 35                                              PCH-5F     11.0       PCH-5F     13.0                                         PCH-6F     4.0        PCH-7F     10.0                                         PCH-7F     10.0       CCP-2OCF.sub.3                                                                           10.0                                         CCP-2OCF.sub.3                                                                           9.0        CCP-3OCF.sub.3                                                                           13.0                                         CCP-3OCF.sub.3                                                                           13.0       CCP-4OCF.sub.3                                                                           7.0                                          CCP-4OCF.sub.3                                                                           7.0        CCP-5OCF.sub.3                                                                           11.0                                         CCP-5OCF.sub.3                                                                           11.0       ECCP-3OCF.sub.3                                                                          11.0                                         ECCP-3OCF.sub.3                                                                          10.0       ECCP-3F.F  10.0                                         ECCP-5OCF.sub.3                                                                          8.0        ECCP-3F    8.0                                          ECCP-3F.F  8.0        CBC-33F    3.0                                          CBC-33F    3.0        CBC-53F    2.0                                          CBC-53F    3.0        CBC-SSF    2.0                                          CBC-55F    3.0                                                                Example 36            Example 37                                              PCH-5F     13.0       PCH-5F     13.0                                         PCH-7F     10.0       PCH-7F     10.0                                         CCP-2OCF.sub.3                                                                           10.0       CCP-2OCF.sub.3                                                                           10.0                                         CCP-3OCF.sub.3                                                                           13.0       CCP-3OCF.sub.3                                                                           13.0                                         CCP-4OCF.sub.3                                                                           7.0        CCP-4OCF.sub.3                                                                           7.0                                          CCP-5OCF.sub.3                                                                           11.0       CCP-5OCF.sub.3                                                                           11.0                                         ECCP-3OCF.sub.3                                                                          11.0       ECCP-3F.F  10.0                                         ECCP-3F.F  10.0       ECCP-5F.F  8.0                                          ECCP-5F.F  7.0        ECCP-3F    11.0                                         CBC-33F    3.0        CBC-33F    3.0                                          CBC-53F    3.0        CBC-53F    2.0                                          CBC-55F    2.0        CBC-55F    2.0                                          Example 38            Example 39                                              PCH-5F     12.0       PCH-5F     12.0                                         PCH-7F     10.0       PCH-6F     9.0                                          CCP-2OCF.sub.3                                                                           11.0       PCH-7F     10.0                                         CCP-3OCF.sub.3                                                                           13.0       CCP-2OCF.sub.3                                                                           11.0                                         CCP-4OCF.sub.3                                                                           7.0        CCP-3OCF.sub.3                                                                           13.0                                         CCP-5OCF.sub.3                                                                           12.0       CCP-4OCF.sub.3                                                                           5.0                                          ECCP-3OCF.sub.3                                                                          9.0        CCP-5OCF.sub.3                                                                           12.0                                         ECCP-3F.F  9.0        ECCP-3F.F  9.0                                          ECCP-5F.F  5.0        ECCP-5F.F  5.0                                          ECCP-3F    6.0        ECCP-3F    5.0                                          CBC-33F    3.0        CBC-33F    3.0                                          CBC-53F    2.0        CBC-53F    3.0                                                                CBC-55F    3.0                                          Example 40            Example 41                                              PCH-5F     12.0        PCH-5F    10.0                                         PCH-6F     8.0        PCH-6F     5.0                                          PCH-7F     10.0       PCH-7F     7.0                                          CCP-2OCF.sub.3                                                                           11.0       CCP-2OCF.sub.3                                                                           11.0                                         CCP-3OCF.sub.3                                                                           13.0       CCP-3OCF.sub.3                                                                           13.0                                         CCP-4OCF.sub.3                                                                           5.0        CCP-4OCF.sub.3                                                                           6.0                                          CCP-5OCF.sub.3                                                                           12.0       CCP-5OCF.sub.3                                                                           11.0                                         ECCP-3F.F  11.0       ECCP-3OCF.sub.3                                                                          7.0                                          ECCP-5F.F  8.0        ECCP-5OCF.sub.3                                                                          3.0                                          CBC-33F    4.0        ECCP-3F.F  9.0                                          CBC-53F    3.0        ECCP-5F.F  4.0                                          CBC-55F    3.0        ECCP-3F    7.0                                                                CBC-33F    3.0                                                                CBC-53F    2.0                                                                CBC-55F    2.0                                          Example 42            Example 43                                              PCH-3      19.0       PCH-3      20.00                                        PCH-7F     7.0        PCH-4      8.00                                         CCP-2OCF.sub.3                                                                           11.0       PCH-5F     8.00                                         CCP-3OCF.sub.3                                                                           13.0       PCH-6F     8.00                                         CCP-4OCF.sub.3                                                                           6.0        PCH-7F     7.00                                         CCP-5OCF.sub.3                                                                           12.0       ECCP-3F    7.00                                         ECCP-3OCF.sub.3                                                                          7.0        ECCP-5F    7.00                                         ECCP-3F.F  10.0       CP-3F      12.00                                        ECCP-5F.F  8.0        CP-5F      12.00                                        ECCP-3F    7.0        ECCP-3     11.00                                        Example 44            Example 45                                              PCH-3      20.00      PCH-3      14.00                                        PCH-5F     9.00       PCH-5F     14.00                                        PCH-6F     9.00       PCH-7F     14.00                                        PCH-7F     9.00       PCH-53     10.00                                        ECCP-3F    8.00       ECCP-3F    6.00                                         ECCP-5F    8.00       ECCP-5F    6.00                                         CP-3F      12.00      ECCP-3CF.sub.3                                                                           5.00                                         CP-5F      12.00      CBC-33     5.00                                         ECCP-3     13.00      CBC-53     5.00                                                               CBC-55     5.00                                                               CBC-33F    5.00                                                               CBC-53F    6.00                                                               CBC-55F    5.00                                          Example 46           Example 47                                              PCH-5F     20.00      PCH-3      24.00                                        PCH-6F     15.00      PCH-SF     9.00                                         PCH-7F     15.00      PCH-7F     8.00                                         ECCP-3F    10.00      ECCP-3F    8.00                                         ECCP-5F    10.00      ECCP-SF    8.00                                         CBC-33     5.00       ECCP-3OCF.sub.3                                                                          11.00                                        CBC-53     5.00       ECCP-5OCF.sub.3                                                                          11.00                                        CBC-55     5.00       ECCP-3CF.sub.3                                                                           11.00                                        CBC-33F    5.00       ECCP-3     10.00                                        CBC-53F    5.00                                                               CBC-55F    5.00                                                               Example 48            Example 49                                              PCH-3      24.00      PCH-3      24.00                                        PCH-5F     7.00       CCH-31F    7.00                                         PCH-7F     6.00       CCH-51F    7.00                                         CCH-31F    6.00       ECCP-3F    8.00                                         ECCP-3F    5.00       ECCP-5F    8.00                                         ECCP-5F    5.00       ECCP-3OCF.sub.3                                                                          11.00                                        ECCP-3OCF.sub.3                                                                          11.00      ECCP-5OCF.sub.3                                                                          11.00                                        ECCP-5OCF.sub.3                                                                          11.00      ECCP-3CF.sub.3                                                                           11.00                                        ECCP-3CF.sub.3                                                                           11.00      ECCP-3     13.00                                        ECCP-3     4.00                                                               CP-3F      5.00                                                               CP-5F      5.00                                                               Example 50            Example 51                                              PYP-SN.F   5.00       PCH-5F     10.00                                        PYP-7N.F   5.00       PCH-6F     12.00                                        PCH-3      14.00      PCH-7F     12.00                                        PCH-SF     5.00       ECCP-3F    14.00                                        CCH-31F    7.00       ECCP-5F    14.00                                        CCH-51F    7.00       CP-3F      15.00                                        ECCP-3F    5.00       CP-5F      15.00                                        ECCP-SF    5.00       ECCP-3     8.00                                         ECCP-3OCF.sub.3                                                                          11.00                                                              ECCP-5OCF.sub.3                                                                          11.00                                                              ECCP-3CF.sub.3                                                                           11.00                                                              ECCP-3     4.00                                                               CP-3F      5.00                                                               CP-5F      5.00                                                               Example 52            Example 53                                              PCE-5F      10.00     PCH-3      16.00                                        PCH-6F     10.00      PCH-301    8.00                                         PCH-7F     10.00      CCP-3OCF.sub.3                                                                           9.00                                         ECCP-3F    13.00      CCP-5OCF.sub.3                                                                           8.00                                         ECCP-5F    14.00      ECCP-3OCF.sub.3                                                                          8.00                                         ECCP-3CF.sub.3                                                                           13.00      ECCP-5OCF.sub.3                                                                          7.00                                         CP-3F      15.00      ECCP-3F.F  7.00                                         CP-5F      15.00      ECCP-3F    6.00                                                               ECCP-3CF.sub.3                                                                           7.00                                                               BCH-3OCF.sub.3                                                                           7.00                                                               PTP-102    4.00                                                               PTP-201    4.00                                                               CPTP-301   2.00                                                               CPTP-302   2.00                                                               CPTP-303   3.00                                         Example 54            Example 55                                              PCH-3      18.00      PCH-3      20.00                                        PCH-301    8.00       PCH-301    10.00                                        PYP-3F     5.00       PCH-3OCF.sub.2                                                                           5.60                                         PYP-5OCF.sub.3                                                                           5.00       PCH-4OCF   5.60                                         PYP-7OCF.sub.3                                                                           5.00       PCH-5OCF.sub.2                                                                           5.60                                         CCP-3OCF.sub.3                                                                           9.00       CCP-3OCF.sub.3                                                                           7.00                                         CCP-5OCF.sub.3                                                                           8.00       CCP-5OCF.sub.3                                                                           6.30                                         ECCP-3OCF.sub.3                                                                          8.00       ECCP-3OCF.sub.3                                                                          6.30                                         ECCP-SOCF.sub.3                                                                          7.00       ECCP-SOCF.sub.3                                                                          5.60                                         ECCP-3F.F  5.00       ECCP-3F.F  5.60                                         ECCP-3F    5.00       ECCP-3CF.sub.3                                                                           5.60                                         BCH-3OCF.sub.3                                                                           7.00       BCH-3OCF.sub.3                                                                           7.00                                         CPTP-301   3.00       CPTP-301   3.50                                         CPTP-302   3.00       CPTP-302   2.80                                         CPTP-303   4.00       CPTP-303   3.50                                         Example 56            Example 57                                              PCH-3      20.00      PCH-3      18.00                                        PCH-301    10.00      PCH-5F     12.00                                        PYP-3F     5.60       PCH-6F     12.00                                        Pyp-5F     5.60       PCH-7F     10.00                                        PYP-5OCF.sub.3                                                                           5.60       ECCP-3F    7.00                                         PYP-7OCF.sub.3                                                                           5.60       ECCP-5F    7.00                                         CCP-3OCF.sub.3                                                                           7.00       ECCP-33    5.00                                         CCP-5OCF.sub.3                                                                           6.30       CBC-33     5.00                                         ECCP-3OCF.sub.3                                                                          6.30       CBC-53     5.00                                         ECCP-SOCF.sub.3                                                                          5.60       CBC-55     4.00                                         ECCP-3F.F  5.60       CBC-33F    5.00                                         ECCP-3CF.sub.3                                                                           5.60       CBC-53F    5.00                                         CPTP-301   3.50       CBC-55F    5.00                                         CPTP-302   3.50                                                               CPTP-303   4.20                                                               Example 58                                                                    PCH-3      10.00                                                              PCH-5F     18.00                                                              PCH-6F     14.00                                                              PCH-7F     10.00                                                              ECCP-3F    9.00                                                               ECCP-5F    7.00                                                               CBC-33     5.00                                                               CBC-53     6.00                                                               CBC-55     5.00                                                               CBC-33F    5.00                                                               CBC-53F    6.00                                                               CBC-55F    5.00                                                               ______________________________________                                    

The properties of the mixtures from Examples 30 to 58 are listed in thetable below:

    __________________________________________________________________________              Example                                                             Property  30  31 32  33 34  35 36  37 38                                      __________________________________________________________________________    Clear point [°C.]                                                                100 101                                                                              100 103                                                                              100 101                                                                              101 100                                                                              101                                     Vicosity at 20°                                                                  15  15 15                15 15                                      (mPa.s)                                                                       Δε                                                                        +4.0                                                                              +6.6                                                                             +5.9              +4.0                                                                             +4.6                                    ε.sub.11                                                                        7.0                      6.8                                                                              7.5                                     Δn  0.090                                                                             0.090                                                                            0.084                                                                             0.076                                                                            0.087                                                                             0.084                                                                            0.085                                                                             0.081                                                                            0.081                                   V.sub.(10,0,20) [Volt]                                                                  2.44                                                                              2.40                                                                             2.57                                                                              2.52                                                                             2.27                                                                              2.29                                                                             2.20                                                                              2.26                                                                             2.27                                    __________________________________________________________________________              Example                                                             Property  39  40 41  42 43  44 45  46 47                                      __________________________________________________________________________    Clear point [°C.]                                                                88  90 102 98 82  84 95  89 87                                      Vicosity at 20°                                                                  14  14 15  17 18  18 17  15 16                                      (mPa.s)                                                                       Δε                                                                        +4.0                                                                              +4.0                                                                             +3.9   +8.0                                                                              +7.3                                                                             +4.6                                                                              +2.7                                                                             +8.7                                    ε.sub.11                                                                        6./ 7.0                                                                              6.6    11.9                                                                              11.0                                                                             7.6    12.1                                    Δn  0.081                                                                             0.079                                                                            0.081                                                                             0.090                                                                            0.094                                                                             0.090                                                                            0.105                                                                             0.093                                                                            0.094                                   V.sub.(10,0,20) [Volt]                                                                  2.13                                                                              2.20                                                                             2.33                                                                              1.90                                                                             1.71                                                                              1.75                                                                             2.15                                                                              2.98                                                                             1.82                                    __________________________________________________________________________             Example                                                              Property 48 49 50 51 52 53 54 55 56 57 58                                     __________________________________________________________________________    Clear point [°C.]                                                               84 101                                                                              85 94 94 106                                                                              91 81 73 95 94                                     Vicosity at 20°                                                                 16 20 19 17 17             17                                        (mPa.s)                                                                       Δε                                                                       +7.9                                                                             +8.3                                                                             +10.2    +6.9                                                                             +8.1                                                                             +6.5                                                                             +8.7                                                                             +5.2                                      ε.sub.11                                                                       11.5                                                                             11.8                                                                             14.2     10.4                                                                             11.8                                                                             10.8                                                                             12.8                                                                             8.4                                       Δn 0.089                                                                            0.094                                                                            0.096                                                                            0.074                                                                            0.072                                                                            0.132                                                                            0.125                                                                            0.113                                                                            0.125                                                                            0.105                                                                            0.101                                  V.sub.(10,0,20) [Volt]                                                                 1.86                                                                             1.98                                                                             1.56                                                                             2.42                                                                             2.58                                                                             2.51                                                                             2.12                                                                             2.15                                                                             1.85                                                                             2.03                                                                             2.223                                  __________________________________________________________________________

Further mixtures according to the invention are listed below:

    ______________________________________                                        Example 59            Example 60                                              CCH-301    7.00       PCH-5F     13.0                                         PCH-5F     12.00      PCH-7F     10.0                                         PCH-7F     9.00       CCP-3OCF.sub.3                                                                           13.0                                         CCP-3F.F   13.00      CCP-4OCF.sub.3                                                                           11.0                                         CCP-5F.F   12.00      CCP-5OCF.sub.3                                                                           12.0                                         ECCP-3OCF.sub.3                                                                          11.00      ECCP-3OCF.sub.3                                                                          11.0                                         ECCP-5OCF.sub.3                                                                          8.00       ECCP-5OCF.sub.3                                                                          8.0                                          ECCP-3F.F  12.00      CCP-3F.F   9.0                                          ECCP-3F    7.00       CCP-SF.F   6.0                                          CBC-33F    3.00       CBC-33F    3.0                                          CBC-53F    3.00       CBC-53F    2.0                                          CBC-55F    3.00       CBC-55F    2.0                                          Example 61            Example 62                                              PCH-5F     11.0       PCH-3      20.0                                         PCH-6F     4.0        PCE-4      8.0                                          PCH-7F     10.0       PCH-5      8.0                                          CCP-2OCF.sub.3                                                                           9.0        PCH-6F     8.0                                          CCP-3OCF.sub.3                                                                           13.0       PCH-7F     7.0                                          CCP-4OCF.sub.3                                                                           7.0        CCP-3F.F   7.0                                          CCP-5OCF.sub.3                                                                           11.0       CCP-5F.F   7.0                                          CCP-3F.F   10.0       CP-3F      12.0                                         CCP-5F.F   8.0        CCP-3F     12.0                                         CCP-3F     8.0        ECCP-3     11.00                                        CBC-33F    3.0                                                                CBC-53F    3.0                                                                CBC-55F    3.0                                                                Example 63            Example 64                                              PCH-3      14.00      PCH-5F     20.00                                        PCH-5F     14.00      PCH-6F     15.00                                        PCH-7F     14.00      PCH-7F     15.00                                        PCH-53     10.00      CCP-3F.F   10.00                                        CCP-3F     6.00       CCP-5F.F   10.00                                        CCP-5F     6.00       CBC-33     5.00                                         CCP-3F.F   5.00       CBC-53     5.00                                         CBC-33     5.00       CBC-55     5.00                                         CBC-53     5.00       CBC-33F    5.00                                         CBC-55     5.00       CBC-53F    5.00                                         CBC-33F    5.00       CBC-S5F    5.00                                         CBC-53F    6.00                                                               CBC-55F    5.00                                                               Example 65            Example 66                                              PCH-3      16.00      PCH-3      18.00                                        PCH-301    8.00       PCH-SF     12.00                                        CCP-3OCF.sub.3                                                                           9.00       PCH-6F     12.00                                        CCP-5OCF.sub.3                                                                           8.00       PCH-7F     10.00                                        CCP-3F.F   8.00       CCP-3F.F   7.00                                         CCP-5F.F   7.00       CCP-SF.F   7.00                                         ECCP-3F.F  7.00       ECCP-33    5.00                                         CCP-3F     6.00       CBC-33     5.00                                         ECCP-3CF.sub.3                                                                           7.00       CBC-S3     5.00                                         BCH-3OCF.sub.3                                                                           7.00       CBC-55     4.00                                         PTP-102    4.00       CBC-33F    5.00                                         PTP-201    4.00       CBC-53F    5.00                                         CPTP-301   2.00       CBC-55F    5.00                                         CPTP-302   2.00                                                               CPTP-303   3.00                                                               Example 67                                                                    PCH-3      10.00                                                              PCH-5F     18.00                                                              PCH-6F     14.00                                                              PCH-7F     10.00                                                              CCP-3F.F   9.00                                                               CCP-5F.F   7.00                                                               CBC-33     5.00                                                               CBC-53     6.00                                                               CBC-55     5.00                                                               CBC-33F    5.00                                                               CBC-53F    6.00                                                               CBC-55F    5.00                                                               ______________________________________                                        Example 68                                                                    ______________________________________                                        Composition:                                                                  PCH-3              10.0   %                                                   PCH-SF             18.0   %                                                   PCH-6F             14.0   %                                                   PCH-7F             10.0   %                                                   ECCP-3F            9.0    %                                                   ECCP-5F            7.0    %                                                   CBC-33             5.0    %                                                   CBC-53             6.0    %                                                   CBC-55             5.0    %                                                   CBC-33F            5.0    %                                                   CBC-53F            6.0    %                                                   CBC-55F            5.0    %                                                   S → N                   <-20   °C.                              Clearing point                 +94    °C.                              Viscosity     ν  +20° C.                                                                           16     mm.sup.2 s.sup. -1                      Dielectric anisotropy                                                                       Δε                                                                    1 kHz, 20° C.                                                                     +4.1                                                         ε.sub.∥                                                            1 kHz, 20° C.                                                                     7.1                                                          ε.sub.⊥                                                                1 kHz, 20° C.                                                                     3.0                                            Optical anisotropy  Δn   +0.1006                                        (p0° C., 589 nm)                                                                           n.sub.e    1.5932                                                             n.sub.o    1.4926                                         ______________________________________                                        Example 69                                                                    ______________________________________                                        Composition:                                                                  PCH-3              18.0   %                                                   PCH-5F             12.0   %                                                   PCH-6F             12.0   %                                                   PCH-7F             10.0   %                                                   ECCP-3F            7.0    %                                                   ECCP-5F            7.0    %                                                   ECCP-33            5.0    %                                                   CBC-33             5.0    %                                                   CBC-53             5.0    %                                                   CBC-55             4.0    %                                                   CBC-33F            5.0    %                                                   CBC-53F            5.0    %                                                   CBC-55F            5.0    %                                                   S → N                   <-40   °C.                              Clearing point                 +95    °C.                              Viscosity     ν  +20° C.                                                                           17     mm.sup.2 s.sup.-1                       Dielectric anisotropy                                                                       Δε                                                                    1 kHz, 20° C.                                                                     +5.2                                                         ε.sub.∥                                                            1 kHz, 20° C.                                                                     8.4                                                          ε.sub.⊥                                                                1 kHz, 20° C.                                                                     3.2                                            Optical anisotropy  Δn   +0.1050                                        (° C., 589 nm)                                                                             n.sub.e    1.5981                                                             n.sub.o    1.4931                                         ______________________________________                                        Example 70                                                                    ______________________________________                                        Composition:                                                                  PCH-3              7.0    %                                                   PCH-5F             12.0   %                                                   PCH-6F             12.0   %                                                   PCH-7F             10.0   %                                                   ECCP-3F            7.0    %                                                   ECCP-5F            7.0    %                                                   PCH-53             8.0    %                                                   ECCP-33            5.0    %                                                   CBC-33             5.0    %                                                   CBC-53             6.0    %                                                   CBC-55             9.0    %                                                   CBC-33F            5.0    %                                                   CBC-53F            6.0    %                                                   CBC-55F            5.0    %                                                   S → N                   <-20   °C.                              Clearing point                 +98    °C.                              Viscosity     ν  +20° C.                                                                           16     mm.sup.2 s.sup.-1                       Dielectric anisotropy                                                                       Δε                                                                    1 kHz, 20° C.                                                                     +3.2                                                         ε∥                                                                 1 kHz, 20° C.                                                                     6.0                                                          ε.sub.⊥                                                                1 kHz, 20° C.                                                                     2.8                                            Optical anisotropy  Δn   +0.1008                                        (20° C., 589 nm)                                                                           n.sub.e    1.5942                                                             n.sub.o    1.4934                                         ______________________________________                                        Exemples   71             72                                                  ______________________________________                                        S → N [°C.]                                                                           <0               <0                                     Clearing point        +100             +101                                   [°C.]                                                                  Viscosity             16               16                                     [mm.sup.2 s.sup. -1 ] 20° C.                                           Δn              +0.086           +0.086                                 (20° C., 589 nm)                                                       n.sub.e               1.558            1.556                                  (20° C., 589 nm)                                                       V.sub.(10,0,20)       2.33             2.38                                   V.sub.(50,0,20)       2.86             2.92                                   V.sub.(20,0,20)       3.52             3.62                                   Composition                                                                              EPCH-      13.0    EPCH-    13.0                                   [%]:       3OCF3              3OCF3                                                      PCH-7F     10.0    EPCH-    10.0                                                                 6OCF3                                                      CCP-2OCF3  10.0    CCP-2OCF3                                                                              10.0                                              CCP-3OCF3  13.0    CCP-30CF3                                                                              13.0                                              CCP-4OCF3  7.0     CCP-4OCF3                                                                              7.0                                               CCP-6OCF3  11.0    CCP-6OCF3                                                                              11.0                                              ECCP-3F.F  10.0    ECCP-3F.F                                                                              10.0                                              ECCP-3F.F  6.0     ECCP-3F.F                                                                              6.0                                               ECCP-3F    11.0    ECCP-3F  11.0                                              CBC-33F    3.0     CVC-33F  3.0                                               CBC-63F    2.0     CBC-63F  2.0                                               CBC-66F    2.0     CBC-66F  2.0                                    ______________________________________                                    

The liquid crystal mixtures according to the invention can contain, inaddition to component B and, where present, A and C, still furtheradditives such as, for example, chiral doping substances, isotropicadditives for modifying various parameters, pleochroic dyes and thelike. Components A, B and C preferably comprise predominantly thecompounds mentioned (that is, more than 50%, in particular more than60%, of them). However, in a preferred manner, components A, B and Ccomprise the compounds mentioned (that is, more than 80%, in particular100% of them).

We claim:
 1. Matrix liquid crystal display containingtwo plane parallelsupport plates which together with a frame form a cell, integratednon-linear elements for switching individual picture elements on thesupport plates and a nematic liquid crystal mixture which is present inthe cell and has a positive dielectric anisotropy and high resistivity,characterized in that the liquid crystal mixture is based on thefollowing components:(a) at least 10% by weight of a liquid-crystallinecomponent B comprising one or more compounds having a dielectricanisotropy of more than +1.5, ##STR16## in which R is n-alkyl orn-alkenyl of up to 9 carbon atoms, X is F, Cl, --CF₃, --CHF₂, --OCF₃,--OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A² and A³ are each,independently of one another, 1,4-phenylene, 2-or3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR17## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ -- or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5 selected fromthe compounds of the formulae VII to XI, ##STR18## in which R¹ and R²have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of 30 mPA.s and a mean dielectricity constant ofε≦8.
 2. Display according to claim 1, characterized in that component Acontains one or more compounds selected from the group consisting of II1to II7: ##STR19## in which R¹ and R² have the meaning given in claim 1.3. Display according to claim 2, characterized in that component Aadditionally contains one or more compounds selected from the groupconsisting of II8 to II20: ##STR20## in which R¹ and R² have the meaninggiven in claim 1 and the 1,4-phenylene groups in I8 to II17 can each,independently of one another, also be mono- or polysubstituted byfluorine.
 4. Display according to claim 2, characterized in thatcomponent A additionally contains one or more compounds selected fromthe group consisting of II21 to II25: ##STR21## in which R¹ and R² havethe meaning given in claim 1 and the 1,4-phenylene groups in II21 toII25 can each, independently of one another, also be mono- orpolysubstituted by fluorine.
 5. Display according to claim 1,characterized in that the liquid crystal mixture additionally contains,in addition to components A, B and C, one or more compounds selectedfrom the group consisting of III and IV: ##STR22## in which R¹ and R²have the meanings given in claim
 1. 6. Display according to claim 1,characterized in that the liquid crystal mixture additionally contains,in addition to components A, B and C, one or more compounds of theformula ##STR23## in which R¹ and R² have the meaning given in claim1and Z⁰ is a single bond, --CH₂ CH₂ --, ##STR24##
 7. Matrix liquidcrystal display containingtwo plane parallel support plates whichtogether with a frame form a cell, integrated non-linear elements forswitching individual picture elements on the support plates and anematic liquid crystal mixture which is present in the cell and has apositive dielectric anisotropy and high resistivity, characterized inthat the liquid crystal mixture is based on the following components:(a)at least 10% by weight Of a liquid-crystalline component B comprisingone or more compounds having a dielectric anisotropy of more than +1.5,##STR25## in which R is n-alkyl or n-alkenyl of up to 9 carbon atoms, Xis cyano, --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or--OC₂ F₅, and the rings A¹, A² and A³ are each, independently of oneanother, 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene,2,3-difluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene,b) up to 90% by weight of a liquid-crystallinecomponent A comprising one or more compounds having a dielectricanisotropy of -1.5 to +1.5 of the general formula I ##STR26## in whichR¹ and R² are each, independently of one another, n-alkyl, ω-fluoroalkylor n-alkenyl having up to 9 carbon atoms, the rings A¹, A² and A³ areeach, independently of one another, 1,4-phenylene 2- or3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or 1,4-cyclohexenylene,Z¹ and Z² are each, independently of one another, --CH₂ CH₂ -- or asingle bond, and m is 0, 1 or 2, andc) 0 to 20% by weight of aliquid-crystalline component C comprising one or more compounds having adielectric anisotropy of less than -1.5, selected from the compounds ofthe formulae VII to XI, ##STR27## in which R¹ and R² have the meaninggiven above and s is 0 or 1, and the nematic liquid crystal mixture hasa nematic phase range of at least 60° C., a maximum viscosity at 20° C.of 30 mPA.s and a mean dielectricity constant of ε≦8, characterized inthat component B consists essentially of nitrile-free, fluorinatedcompounds.
 8. Matrix liquid crystal display containingtwo plane parallelsupport plates which together with a frame form a cell, integratednon-linear elements for switching individual picture elements on thesupport plates and a nematic liquid crystal mixture which is present inthe cell and has a positive dielectric anisotropy and high resistivity,characterized in that the liquid crystal mixture is based on thefollowing components:(a) at least 10% by weight of a liquid-crystallinecomponent B comprising one or more compounds having a dielectricanisotropy of more than +1.5, ##STR28## in which R is n-alkyl orn-alkenyl of up to 9 carbon atoms, X is cyano, --NCS, F, Cl, --CF₃,--CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A²and A³ are each, independently of one another, 1,4-phenylene, 2-or3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR29## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ --or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5, selectedfrom the compounds of the formulae VII to XI, ##STR30## in which R¹ andR² have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity of 20° C. of 30 mPA.s and a mean dielectricity constant ofε≦8, characterized in that component B contains compounds of theformulae IIa to IIf in which X is cyano and compounds of the formulaeIIa to IIf in which X is --NCS, F, Cl, --CF₃, --CHF₃, --OCF₃, --OCHF₂,--OCF₂ CF₂ H or --OC₂ F₅ and the amount of cyano compounds in componentB is 0 to 50% by weight.
 9. Display according to claim 8, characterizedin that component B does not contain any compounds of the formulae IIato IIf in which X is cyano.
 10. Matrix liquid crystal displaycontainingtwo plane parallel support platers which together with a frameform a cell, integrated non-linear elements for switching individualpicture elements on the support plates and a nematic liquid crystalmixture which is present in the cell and has a positive dielectricanisotropy and high resistivity, characterized in that the liquidcrystal mixture is based on the following components:(a) at least 10% byweight of a liquid-crystalline component B comprising one or morecompounds having a dielectric anisotropy of more than +1.5, ##STR31## inwhich R is n-alkyl or n-alkenyl of up to 9 carbon atoms, X is cyano,--NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅,and the rings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2-or 3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR32## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ -- or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5, selectedfrom the compounds of the formulae VII to XI, ##STR33## in which R¹ andR² have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of 30 mPA.s and a mean dielectricity constant ofε≦8, characterized in that X is F, Cl, CF₃, --OCF₃, --OCHF₂ or --CHF₂.11. Matrix liquid crystal display containingtwo plane parallel supportplates which together with a frame form a cell, integrated non-linearelements for switching individual picture elements on the support platesand a nematic liquid crystal mixture which is present in the cell andhas a positive dielectric anisotropy and high resistivity, characterizedin that the liquid crystal mixture is based on the followingcomponents:(a) at least 10% by weight of a liquid-crystalline componentB comprising one or more compounds having a dielectric anisotropy ofmore than +1.5, ##STR34## in which R is n-alkyl or n-alkenyl of up to 9carbon atoms, X is cyano, --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂,--OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A² and A³ are eachindependently of one another, 1,4-phenylene, 2-or3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR35## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ -- or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5, selectedfrom the compounds of the formulae VII to XI, ##STR36## in which R¹ andR² have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of 30 mPA.s and a mean dielectricity constant ofε≦8, characterized in that component A contains one or more compoundsselected from the group consisting of II26 and II27: ##STR37## in whichC_(r) H_(2r+1) is a straight-chain alkyl group of up to 7 carbon atoms.12. Matrix liquid crystal display containingtwo plane parallel supportplates which together with a frame form a cell, integrated non-linearelements for switching individual picture elements on the support platesand a nematic liquid crystal mixture which is present in the cell andhas a positive dielectric anisotropy and high resistivity, characterizedin that the liquid crystal mixture is based on the followingcomponents:(a) at least 10% by weight of a liquid-crystalline componentB comprising one or more compounds having a dielectric anisotropy ofmore than +1.5, ##STR38## in which R is n-alkyl or n-alkenyl of up to 9carbon atoms, X is cyano, --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂,--OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A² and A³ are eachindependently of one another, 1,4-phenylene, 2-or 3-fluoro,1,4-phenylene, 2,3-difluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene,b) up to 90% by weight of a liquid-crystallinecomponent A comprising one or more compounds having a dielectricanisotropy of -1.5 to +1.5 of the general formula I ##STR39## in whichR¹ and R² are each, independently of one another, n-alkyl, ω-fluoroalkylor n-alkenyl having up to 9 carbon atoms, the rings A¹, A² and A³ areeach independently of one another, 1,4-phenylene, 2- or3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or 1,4-cyclohexenylene,Z¹ and Z² are each independently of one another, --CH₂ CH₂ -- or asingle bond, and m is 0, 1 or 2, andc) 0 to 20% by weight of aliquid-crystalline component C comprising one or more compounds having adielectric anisotropy of less than -1.5, selected from the compounds ofthe formulae VII to XI, ##STR40## in which R¹ and R² have the meaninggiven above and s is 0 or 1, and the nematic liquid crystal mixture hasa nematic phase range of at least 60° C., a maximum viscosity at 20° C.of 30 mPA.s and a mean dielectricity constant of ε≦8, characterized inthat the liquid crystal mixture additionally contains, in addition tocompounds A, B and C, one or more compounds selected from the groupconsisting of V and VI: ##STR41## in which R¹ and R² have the meaninggiven above.
 13. Matrix liquid crystal display containingtwo planeparallel support plates which together with a frame form a cell,integrated non-linear elements for switching individual picture elementson the support plates and a nematic liquid crystal mixture which ispresent in the cell and has a positive dielectric anisotropy and highresistivity, characterized in that the liquid crystal mixture is basedon the following components:(a) at least 10% by weight of aliquid-crystalline component B comprising one or more compounds having adielectric anisotropy of more than +1.5, ##STR42## in which R is n-alkylor n-alkenyl of up to 9 carbon atoms, X is cyano, --NCS, F, Cl, --CF₃,--CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A²and A³ are each, independently of one another, 1,4-phenylene, 2-or3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR43## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ -- or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5, selectedfrom the compounds of the formulae VII to XI, ##STR44## in which R¹ andR² have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of 30 mPA.s and a mean dielectricity constant ofε≦8, characterized in that the liquid crystal mixture additionallycontains, in addition to components A, B and C, one or more compoundsselected from the group consisting of VII to XI: ##STR45## in which R¹and R² have the meaning given above and s is 0 or
 1. 14. Matrix liquidcrystal display containingtwo plane parallel support plates whichtogether with a frame form a cell, integrated non-linear elements forswitching individual picture elements on the support plates and anematic liquid crystal mixture which is present in the cell and has apositive dielectric anisotropy and high resistivity, characterized inthat the liquid crystal mixture is based on the following components:(a)at least 10% by weight of a liquid-crystalline component B comprisingone or more compounds having a dielectric anisotropy of more than +1.5,##STR46## in which R is n-alkyl or n-alkenyl of up to 9 carbon atoms, Xis cyano, --NCS, F, Cl, --CF₃, --CHF₂, --OCF₃, --OCHF₂, --OCF₂ CF₂ H or--OC₂ F₅, and the rings A¹, A² and A³ are each, independently of oneanother, 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene,2,3-difluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene,b) up to 90% by weight of a liquid-crystallinecomponent A comprising one or more compounds having a dielectricanisotropy of -1.5 to +1.5 of the general formula I ##STR47## in whichR¹ and R² are each, independently of one another, n-alkyl, ω-fluoroalkylor n-alkenyl having up to 9 carbon atoms, the rings A¹, A² and A³ areeach, independently of one another, 1,4-phenylene, 2- or3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or 1,4-cyclohexenylene,Z¹ and Z² are each independently of one another, --CH₂ CH₂ -- or asingle bond, and m is 0, 1 or 2, andc) 0 to 20% by weight of aliquid-crystalline component C comprising one or more compounds having adielectric anisotropy of less than -1.5, selected from the compounds ofthe formulae VII to XI, ##STR48## in which R¹ and R² have the meaninggiven above and s is 0 or 1, and the nematic liquid crystal mixture hasa nematic phase range of at least 60° C., a maximum viscosity at 20° C.of 30 mPA.s and a mean dielectricity constant of ε≦8, which contains≦20% of components of formulae IIa-IIf wherein X denotes nitrile andcontains compounds which conforms to formulae IIa to IIf where X is--OCF₃, --OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅.
 15. A nematic liquid crystalmixture which has a positive dielectric anisotropy and highresistivity,characterized in that the liquid crystal mixture consistsessentially of the following components:(a) at least 10% by weight of aliquid-crystalline component B comprising one or more compounds having adielectric anisotropy of more than +1.5, ##STR49## in which R is n-alkylor n-alkenyl of up to 9 carbon atoms, X is F, Cl, --CF₃, --CHF₂, --OCF₃,--OCHF₂, --OCF₂ CF₂ H or --OC₂ F₅, and the rings A¹, A² and A³ are each,independently of one another, 1,4-phenylene, 2-or3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,trans-1,4-cyclohexylene or 1,4-cyclohexenylene,b) up to 90% by weight ofa liquid-crystalline component A comprising one or more compounds havinga dielectric anisotropy of -1.5 to +1.5 of the general formula I##STR50## in which R¹ and R² are each, independently of one another,n-alkyl, ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, therings A¹, A² and A³ are each, independently of one another,1,4-phenylene, 2- or 3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, Z¹ and Z² are each, independently of one another,--CH₂ CH₂ -- or a single bond, and m is 0, 1 or 2, andc) 0 to 20% byweight of a liquid-crystalline component C comprising one or morecompounds having a dielectric anisotropy of less than -1.5 selected fromthe compounds of the formulae VII to XI, ##STR51## in which R¹ and R²have the meaning given above and s is 0 or 1, and the nematic liquidcrystal mixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of mPA.s and a mean dielectricity constant of ε≦8.